DE202020000985U1 - Auxiliary device for a method for welding connections between inner tubes and tube support plates of a tube bundle for a product-to-product tube bundle heat exchanger - Google Patents

Abstract

Auxiliary device (50) for a method for welded connections between inner tubes (16) and tube support plates (12, 14) of a tube bundle (10) for a product-to-product tube bundle heat exchanger (100), the welded connection being in a manner known per se the inner tube (16) is connected with its inner bore (17) in a plane perpendicular to an inner tube longitudinal axis (R) to an end face of the disk-shaped tube support plate (12, 14), which has the same inner bore (17), • that the inner bore (17) of the inner tube (16) and that of the tube support plate (12, 14) have equal inner diameters (D) and are aligned with each other, • that in an unwelded starting position the inner tube (16) and the tube support plate (12, 14) are fixed to one another with a first positive connection (F1), which is effective radially, axially and in the opposite direction, • that a circumferential circular weld seam (36) orbital, from the inner bore (17), is single-layer and continuous from the inside to the outside and • that a weld seam width (b) of the circumferential circular weld seam (36) detects at least one axial form-fit depth (B1) of the first form-fit (F1), characterized , • that a first and a second retaining ring half (50.1, 50.2) are provided which form a closed ring, • that the retaining ring halves (50.1, 50.2) are in a parting plane (E) through a center (Z) of the auxiliary device ( 50), touch and that in the parting plane (E) the retaining ring halves (50.1, 50.2) form an immovable second form fit (F2) with each other, • that the tube support plate (12, 14) by specifying more than one internal bore provided in it (17) defines a pipe occupancy pattern (M) for the arrangement of inner tubes (16) arranged parallel to one another, • that the tube occupancy pattern (M) is depicted in the retaining ring halves (50.1, 50.2) in this way is that on a single pitch circle (T), evenly distributed inner tubes (16) are each enclosed on a maximum half side by the retaining ring halves (50.1, 50.2), the opening of the respective surrounding contour facing the center (Z) of the retaining ring halves (50.1, 50.2) is that • the parting plane (E) also runs through at least one inner tube longitudinal axis (R) lying on the pitch circle (T), • that retaining bolts (52) are provided, each on the circumference of the retaining ring halves (50.1, 50.2) and in a star shape towards the center (Z) oriented to engage in the retaining ring halves (50.1, 50.2) so that the retaining bolts (52) on the pitch circle (T) arranged adjacent inner tubes (16) each tangent and • that the retaining bolts (52) with their respective If necessary, fix an inner tube (16) arranged in the center (Z) to the center (Z) facing the end face and are each detachably fixed in this position.

Description

TECHNICAL AREA

The innovation relates to an auxiliary device for a method for welded connections between inner tubes and tube support plates of a tube bundle for a tube bundle heat exchanger, preferably a product-to-product tube bundle heat exchanger. The respective welded connection is designed in such a way that the inner tube is connected with its inner bore in a plane perpendicular to an inner tube longitudinal axis to an end face of the disk-shaped tube support plate, which has the same inner bore. The inner bore of the inner tube and that of the tube support plate have equal inner diameters and are aligned with one another. In a non-welded starting position, the inner tube and the tube support plate are fixed to one another with a first positive connection, which is effective radially, axially and in the opposite direction. A circumferential circular weld seam is orbital, starting from the inner bore, single-layer and continuous from the inside to the outside, and a weld seam width of the circumferential circular weld seam detects at least one axial form-fit depth of the first positive fit. The innovation further relates to a tube bundle welded with such an auxiliary device and a product-to-product tube bundle heat exchanger with at least one such tube bundle.

STATE OF THE ART

Various types of heat exchangers are used in the food and beverage industry to heat food products. The respective selection, for example plate or tube heat exchangers in their most varied embodiments, depends on the food product to be treated. The tubular heat exchanger is suitable for low-viscosity products such as milk and other milk products, beverages and juices as well as for medium to high-viscosity products such as concentrates, soups or desserts and also for products of this type that also contain fibers and / or pulp. As a rule, for the purpose of heat treatment, the product flows through the so-called inner tubes and a heat transfer medium, for example steam or water, flows around these inner tubes, preferably in countercurrent, from the outside in a housing, preferably a jacket tube, surrounding the inner tubes.

A particularly energy-efficient embodiment of the known tube heat exchanger is a so-called tube bundle heat exchanger (see 1 ). This consists of a large number of tube bundles ( 2a , 2 B , 3rd ), each of which has several inner tubes connected in parallel with a common inlet and outlet for the product. The respective group of inner tubes or a so-called set of inner tubes is enclosed by the jacket tube, which is provided near its ends with a radially opening or ending connecting piece for a heat transfer medium. The heat transfer medium flows through the jacket tube, preferably in countercurrent to the tube flow in the inner tubes, a product stream.

The inner tubes each penetrate a bore in a so-called tube support plate at the end and are each connected at their outlet end to the tube support plate by means of a circumferential circular weld seam. There is therefore a circumferential annular gap between the outside of the inner tube and the associated bore in the tube support plate, which extends from the circumferential welded seam into an interior of the tube bundle or the jacket tube, which is acted upon by the heat transfer medium. This circumferential annular gap is not critical as long as the heat transfer medium only remains heat transfer medium such as water or steam and is not substituted by a food product.

However, if a so-called product-to-product heat transfer is to take place in a tube bundle heat exchanger for reasons of improved heat transfer efficiency, then the aforementioned circumferential annular gap becomes critical because product can settle here, which in the best case can only be achieved by particularly intensive and long-lasting CIP -Cleaning (overdosed cleaning) can be cleaned so that the circumferential annular gap is in a microbiologically uncritical state for the subsequent product run.

Particularly in the case of regeneratively operated heat transfer systems, in which, for example, the heat generated during the cooling of an end product is used to preheat a product that is still to be treated, it is known that there is heat transfer from product to product ( PP ) against heat transfer from product-to-heat transfer medium to product ( PWP ) higher energy efficiency or economy because the heat transfer can be improved by a larger logarithmic temperature difference and a higher flow velocity of the product flows (higher Reynolds number) and the heat exchange surfaces can be reduced. The higher Reynolds numbers also allow tube bundles with longer tube lengths to be realized, which results in cost reductions.

In the known form, the tube bundle heat exchangers are only suitable from a sanitary or even aseptic point of view for the price of overdosed cleaning for a product-to-product heat exchange. It was therefore proposed ( JP 2020 117 121 ), to perform an additional round seam weld on the back of the tube carrier plate in order to close the critical annular gap against product penetration. A disadvantage of a respective circumferential circular weld seam on the front and additionally on the rear of the tube support plate is that a closed space is formed between the two circular weld seams, which poses a risk to food safety if the circular weld seams are not welded without defects and without pores. A check in this regard is difficult or not possible at all. There is then a risk that microorganisms can settle in the closed space, which can recontaminate a subsequent product.

In the US 2 996 600 A. describes a welded connection between a pipe and a pipe support plate in the context of a pipe heat exchanger. The tube has an inside diameter that corresponds to the diameter of a hole in the tube support plate. The tube and the tube support plate are welded together in such a way that the inside diameter of the tube and the diameter of the bore are aligned. The necessary alignment and centering of the pipe on the pipe support plate is achieved by a recess on the pipe support plate into which the pipe engages. A reversal of this principle is also disclosed, in which a recess is provided at the pipe end to be connected, which recess surrounds a neck surrounding the bore in the pipe support plate from the outside. The respective interlocking area between the pipe and the pipe support plate is welded in one layer and continuously from the inside to the outside using an orbital circumferential welding tool, starting from the inside of the inside diameter of the pipe and the bore of the pipe support plate.

In the WO 2014 060 425 A1 A wide variety of proposals are disclosed as to how the connection in question between an inner tube and a tube support plate of a tube bundle of a tube bundle heat exchanger can be designed while avoiding a circumferential annular gap between the outside of the inner tube and the bore in the tube support plate.

Starting from the aforementioned prior art, it is the object of the present innovation to create an auxiliary device of the generic type which provides a secure, dimensionally accurate and high-quality, reproducible weld connection between the inner tubes and the tube support plate of a tube bundle for a product-to-product Tube bundle heat exchanger ensures.

SUMMARY OF THE INNOVATION

This object is achieved by an auxiliary device with the features of claim 1. Advantageous embodiments of the auxiliary device according to the invention are the subject of the associated subclaims. A tube bundle is the subject of dependent claim 9 and a product-to-product tube bundle heat exchanger with at least one such tube bundle is the subject of claim 10.

• • Das Innenrohr mit seiner Innenbohrung ist in einer Ebene senkrecht zu einer Innenrohrlängsachse mit einer Stirnseite der scheibenförmigen Rohrträgerplatte, die eine ebensolche Innenbohrung aufweist, verbunden.
• • Die Innenbohrung des Innenrohres und jene der Rohrträgerplatte weisen gleichgroße Innendurchmesser auf und sind miteinander fluchtend ausgerichtet, d.h. ihre Rotationsachsen verlaufen koaxial.
• • In einer unverschweißten Ausgangslage sind das Innenrohr und die Rohrträgerplatte mit einem ersten Formschluss, der radial sowie axial und gegeneinander gerichtet wirksam ist, zueinander festgelegt. Die radiale Festlegung wirkt in beiden Richtungen, die axiale Festlegung beschränkt sich darauf, dass das Innenrohr an der Rohrträgerplatte in der einen Richtung anliegt und in der umgekehrten Richtung von dieser gelöst werden kann.
• • Eine umlaufende Rundschweißnaht ist orbital, von der Innenbohrung ausgehend, einlagig und durchgängig von innen bis außen ausgeführt. Die Schweißung erfolgt vorzugsweise ohne Zusatzmaterial und unter einer für die zu verbindenden Materialien geeigneten Schutzgasatmosphäre.
• • Eine Schweißnahtbreite der umlaufenden Rundschweißnaht erfasst mindestens eine axiale Formschlusstiefe des ersten Formschlusses. Die axiale Formschlusstiefe ist auf eine sich unter den gegebenen Schweiß- und Wandstärkenbedingungen ergebende Schweißnahtbreite abgestimmt. Die axiale Formschlusstiefe darf eine mögliche Schweißnahtbreite nicht überschreiten. Unter umlaufender Rundschweißnaht ist eine Schweißnaht zu verstehen, die in sich geschlossen, d.h. ohne örtliche Unterbrechungen ausgeführt ist.

The innovation is based on a welded connection, which is designed as follows:

• • The inner tube with its inner bore is connected in a plane perpendicular to an inner tube longitudinal axis with an end face of the disk-shaped tube support plate, which has the same inner bore.
• • The inner bore of the inner tube and that of the tube support plate have equal inner diameters and are aligned with one another, ie their axes of rotation run coaxially.
• • In a non-welded starting position, the inner tube and the tube support plate are fixed to one another with a first positive connection, which is effective radially, axially and in opposite directions. The radial fixation acts in both directions, the axial fixation is limited to the fact that the inner tube lies against the tube support plate in one direction and can be detached from it in the opposite direction.
• • A circumferential circular weld seam is orbital, starting from the inner bore, single-layer and continuous from the inside to the outside. The welding is preferably carried out without additional material and under a protective gas atmosphere suitable for the materials to be joined.
• • A weld seam width of the circumferential circular weld seam detects at least one axial form-fit depth of the first form-fit. The axial form-fit depth is matched to a weld seam width that results under the given welding and wall thickness conditions. The axial form-fit depth must not exceed a possible weld seam width. A circumferential circular weld seam is to be understood as a weld seam which is self-contained, that is to say is carried out without local interruptions.

The basic idea of the innovation in the case of the auxiliary device according to the invention is to provide a solution not only for a single inner tube, as disclosed in the prior art, but a solution for a group or a set of inner tubes running parallel to one another in the sense of the task to propose a continuous welding process that covers all the inner tubes of the set one after the other.

• • Es sind im Rahmen der Hilfsvorrichtung eine erste und eine zweite Halteringhälfte vorgesehen, die einen geschlossenen Ring bilden.
• • Die Halteringhälften berühren sich in einer Trennebene, die durch ein Zentrum der Hilfsvorrichtung verläuft, und in der Trennebene bilden die Halteringhälften einen unverschieblichen zweiten Formschluss miteinander.
• • Die Rohrträgerplatte legt durch die Vorgabe von mehr als einer in ihr vorgesehenen Innenbohrung ein Rohrbelegungsmuster fest für die Anordnung parallel zueinander angeordneter Innenrohre.
• • Das Rohrbelegungsmuster ist in den Halteringhälften derart abgebildet, dass auf einem einzigen Teilkreis gleichverteilt angeordnete Innenrohre jeweils maximal halbseitig von den Halteringhälften umschlossen sind, wobei die Öffnung der jeweils umschließenden Kontur dem Zentrum der Halteringhälften zugewandt ist. Diese Bedingungen werden durch entsprechende Bemessung eines Innendurchmessers der zu einem Ring geschlossenen Halteringhälften erfüllt, wobei die Bemessung von der Anzahl der auf dem Teilkreis befindlichen Innenrohre abhängt.
• • Die Trennebene verläuft zusätzlich durch mindestens eine auf dem Teilkreis liegende Innenrohrlängsachse. Dadurch ist sichergestellt, dass die Halteringhälften sämtliche Innenrohre umschließen und in Gänze festlegen können und dass nach dem Verschweißen aller Innenrohre mit der Rohrträgerplatte ein Lösen und Entfernen der Halteringhälften von der verschweißten Rohranordnung möglich ist.
• • Es sind Haltebolzen vorgesehen, die jeweils am Umfang der Halteringhälften und sternförmig zum Zentrum hin orientiert in die Halteringhälften verschieblich eingreifen.
• • Die Haltebolzen tangieren mit ihrer Mantelfläche jeweils auf dem Teilkreis angeordnete, benachbarte Innenrohre.
• • Die Haltebolzen legen mit ihrer jeweiligen dem Zentrum zugewandten Stirnseite erforderlichenfalls ein im Zentrum angeordnetes Innenrohr fest und sind in dieser Position selbst jeweils lösbar festgelegt.

The task underlying the innovation is solved by the following features.

• • A first and a second retaining ring half are provided as part of the auxiliary device, which form a closed ring.
• • The retaining ring halves touch in a parting plane, which runs through a center of the auxiliary device, and in the parting plane, the retaining ring halves form an immovable second form fit with one another.
• • By specifying more than one inner bore provided in it, the pipe support plate defines a pipe assignment pattern for the arrangement of inner pipes arranged parallel to one another.
• • The tube occupancy pattern is depicted in the retaining ring halves in such a way that inner tubes which are arranged in a uniformly distributed manner on a single pitch circle are enclosed by the retaining ring halves on a maximum of half sides, the opening of the respective surrounding contour facing the center of the retaining ring halves. These conditions are met by appropriate dimensioning of an inner diameter of the retaining ring halves closed to form a ring, the dimensioning depending on the number of inner tubes located on the pitch circle.
• • The parting plane also runs through at least one inner tube longitudinal axis lying on the pitch circle. This ensures that the retaining ring halves can enclose and fix all of the inner tubes and that after the welding of all inner tubes to the tube support plate, the retaining ring halves can be detached and removed from the welded tube arrangement.
• • Retaining bolts are provided, each of which can be slidably engaged in the retaining ring halves on the circumference of the retaining ring halves and in a star shape towards the center.
• • The retaining bolts touch with their outer surface each adjacent inner tubes arranged on the pitch circle.
• • If necessary, the retaining bolts with their respective end faces facing the center fix an inner tube arranged in the center and are themselves detachably fixed in this position.

An auxiliary device designed in accordance with the above features is suitable for receiving pipe arrangements with at least two inner pipes as intended.

It is sufficient if the second form-fit locks the first and the second half-ring halves in a radial direction to one another. The fixing of the retaining ring halves in the axial direction to one another expediently takes place in such a way that the first and the second half ring halves are detachably connected to one another by a connecting screw arranged on the circumference of the first and the second half ring halves, which are arranged diametrically to one another.

If the auxiliary device is in the closed position and in this position it fixes a specified number of inner tubes so that they can be welded to the associated tube support plate, then the retaining bolts, which fix the inner tubes in the second form fit, are each by a locking screw in the assigned retaining ring half itself immovably.

A particularly advantageous pipe occupancy pattern is characterized in that seven inner pipes are provided, one inner pipe being located coaxially in the center of the auxiliary device and six inner pipes being evenly distributed on the pitch circle, and in that the parting plane additionally runs through two diametrically arranged inner pipes. In this arrangement, the inner tube longitudinal axes of three adjacent inner tubes form the corners of an equilateral triangle, as a result of which the radial spacing of all adjacent inner tubes is of the same size, since as a rule all of the inner tubes have the same outer diameter. The heat transfer and heat transfer conditions are approximately the same for all inner tubes under these boundary conditions, if one disregards the special flow conditions of the central inner tube compared to the other inner tubes located on the pitch circle.

A very simple configuration of the connection geometry between the inner tube and the tube support plate is realized with the aid of the new device if the circumferential circular weld seam is positioned such that the weld seam width engages in the tube support plate by the form depth as seen from the side of the inner tube. In this case it is Pipe support plate only with the outside diameter of the inner pipe and with a maximum of the form-fitting depth. This quantitative configuration ensures that there is no longer a gap between the outer diameter of the inner tube and the inner bore in the tube carrier plate, which is not bridged by the circumferential circular weld seam. A counterbore with less than the form-fitting depth shifts part of the width of the circumferential circular weld seam into a pipe area upstream of the pipe carrier plate.

A shift of the circumferential circular weld seam partially or completely into the tube support plate leads in a manner known per se to a discontinuous course of the connection cross sections from the relatively small connection cross section of the inner tube to the solid cross section of the tube support plate. Such a course is unfavorable in terms of strength. In order to remedy this situation, a further proposal that can be realized with the new auxiliary device provides that the tube support plate has a circumferential, axially extending, annular-gap-shaped plate-side recess radially outside of the circumferential circular weld seam, which is designed such that the circumferential circular weld seam is closed welding wall thickness of the tube support plate assumes a value that lies between the simple to twice the tube wall thickness.

Another proposal, which can also be implemented with the auxiliary device according to the invention, also provides a remedy in this regard and in particular improves the strength properties under changing mechanical and / or thermal loads. It provides that the circumferential circular weld seam, relative to the pipe support plate, is positioned at an upstream axial form-fit distance of the first form-fit from the pipe support plate, the pipe support plate in this area having a wall thickness between single and double the pipe wall thickness.

In order to minimize material stresses in the course of the welding process during all welding connections, a welding sequence is provided in such a way that, if available, first an inner tube arranged centrally in the tube carrier plate and then the outer inner tubes arranged on a pitch circle around the central inner tube, each in opposite directions Sequence with which the pipe support plate is welded.

Figure list

• 1 in schematischer und perspektivischer Darstellung einen Rohrbündel-Wärmeaustauscher nach dem Stand der Technik;
• 2a in perspektivischer Darstellung ein Rohrbündel nach dem Stand der Technik mit Blick auf die eine Rohrträgerplatte;
• 2b in perspektivischer Darstellung das Rohrbündel gemäß 2a mit Blick auf die andere Rohrträgerplatte;
• 3 im Meridianschnitt ein Rohrbündel gemäß den 2a, 2b nach dem Stand der Technik, eingebettet in ein Gehäuse für die Zufuhr eines Wärmeträgermediums;
• 4 einen Meridianschnitt durch eine erste Schweißverbindung zwischen einem Innenrohr und einer Rohrträgerplatte in Verbindung mit einem Schweißwerkzeug;
• 4a in vergrößerter Darstellung eine zur Ausgestaltung der ersten Schweißverbindung gemäß 4 alternative zweite Ausgestaltung;
• 4b in vergrößerter Darstellung eine zur Ausgestaltung der ersten Schweißverbindung gemäß 4 alternative dritte Ausgestaltung;
• 5 in vergrößerter Darstellung eine zur Ausgestaltung der ersten Schweißverbindung gemäß 4 alternative vierte Ausgestaltung;
• 6 in vergrößerter Darstellung eine zur Ausgestaltung der ersten Schweißverbindung gemäß 4 alternative fünfte Ausgestaltung;
• 7 in perspektivischer Darstellung eine Rohrträgerplatte für sieben Innenrohre;
• 7a in perspektivischer Darstellung einen Meridianschnitt durch die Rohrträgerplatte gemäß einem in 7 mit „C-C“ gekennzeichneten Schnittverlauf;
• 7b in Ansicht den Meridianschnitt durch die Rohrträgerplatte gemäß 7a;
• 8 in perspektivischer Darstellung eine Gesamtansicht der geschlossenen Hilfsvorrichtung ohne Innenrohre;
• 9 in perspektivischer Darstellung eine Gesamtansicht der geschlossenen Hilfsvorrichtung mit darin festgelegten Innenrohren und
• 10 eine Ansicht der geschlossenen Hilfsvorrichtung entsprechend einer in 8 mit „G“ gekennzeichneten Blickrichtung.

A more detailed description of the innovation results from the following description and the accompanying figures of the drawing and from the claims. The innovation can be implemented in the most varied of embodiments of an inventive auxiliary device of the generic type. The auxiliary device is described below with reference to the drawing using a preferred exemplary embodiment. Show it

• 1 in a schematic and perspective view of a tube bundle heat exchanger according to the prior art;
• 2a a perspective view of a tube bundle according to the prior art with a view of a tube support plate;
• 2 B in perspective the tube bundle according 2a facing the other tube support plate;
• 3rd in the meridian section a tube bundle according to the 2a , 2 B according to the prior art, embedded in a housing for the supply of a heat transfer medium;
• 4th a meridian section through a first welded connection between an inner tube and a tube support plate in connection with a welding tool;
• 4a in an enlarged representation according to the embodiment of the first welded connection 4th alternative second embodiment;
• 4b in an enlarged representation according to the embodiment of the first welded connection 4th alternative third embodiment;
• 5 in an enlarged representation according to the embodiment of the first welded connection 4th alternative fourth embodiment;
• 6 in an enlarged representation according to the embodiment of the first welded connection 4th alternative fifth embodiment;
• 7 in perspective a tube support plate for seven inner tubes;
• 7a a perspective view of a meridian section through the tube support plate according to a in 7 With " CC “Marked cut;
• 7b in view the meridian section through the tube support plate according to 7a ;
• 8th a perspective view of an overall view of the closed auxiliary device without inner tubes;
• 9 a perspective view of an overall view of the closed auxiliary device with inner tubes and fixed therein
• 10th a view of the closed auxiliary device according to one in 8th With " G “Marked viewing direction.

1 shows an embodiment of a tube bundle heat exchanger 100 , in which usually a variety of tube bundles 10th with connecting bow 5 fluidically connected in series. The tube bundle 10th consists of a set with several inner tubes 16 (please refer 2a , 2 B) which run parallel to one another and are also connected in parallel in terms of flow technology, in each case at the end the respective bore in a first and a second tube support plate 12th , 14 penetrate, support there and with their tube outer diameter on the outside end face of the tube support plate 12th , 14 with this all around crappy. Each set of inner tubes 16 is in an outer tube or jacket tube 15 arranged ( 1 ). The product, for example a food product, is through the inner tubes 16 passed, and a so-called heat transfer medium, such as water or steam, flows around the outside of the inner tubes 16 inside the outer tube 15 . The 2a , 2 B each show an annular gap S between an outer diameter of each inner tube 16 and a respectively assigned hole within the tube support plate 12th , 14 is formed.

The tube bundle known from the prior art 10th ( 3rd - only the components relevant here are identified; see also DE 94 03 913 U1 ) consists in its middle part, which is shown interrupted, of the one outer channel 15 * limiting outer tube 15 (or outer jacket) with a non-designated, on the left-hand side, the outer jacket flange arranged on the bearing side and an unsigned, on the right side, the floating jacket outer jacket flange. A first housing with a second inlet connects to the latter 22 and a second housing with a second outlet closes on the outer casing flange on the fixed bearing side 24th at. A number n axially parallel to the outer tube 15 through the outer channel 15 * extending, together an inner channel 16 * forming inner tubes 16 is at the end in the left-hand tube support plate 12th , which is part of a fixed bearing, and the right-hand pipe support plate 14 , which is part of a floating bearing, supported and on its outer tube diameter via a circumferential weld SN welded to this. This overall arrangement is in the outer tube through an unspecified opening on the second housing 15 introduced and via a fixed-side exchanger flange, which is a first entry 18th records, clamped together with the second housing with the interposition of a seal. The inner tube 16 , whose inner tube longitudinal axis is denoted by R, has an inner bore 17th with an inner diameter D on. The fixed bearing side and the floating bearing side tube support plate 12th , 14 have a plate rotation axis A , which are arranged coaxially to each other and which in turn with a central inner tube 16 to its inner tube longitudinal axis R run coaxially. The tube support plate on the floating bearing side 14 is connected to a connecting piece on the floating bearing side, which has a first outlet 20th records.

Depending on the arrangement of the respective tube bundle 10th in the tube bundle heat exchanger 100 and its respective wiring, the inner tubes 16 , based on the presentation, about the first entry 18th either left to right to the first exit 20th or vice versa from a first product P1 which is to be heat-treated are flowed through. At the neighboring tube bundle 10th that with the tube bundle described above 10th each over the connecting arch 5 is connected in series, these entry and exit conditions are reversed accordingly.

The outer channel 15 * can be exposed to a heat transfer medium such as water or steam. In a so-called heat exchange product-to-product, the heat transfer medium is a second product P2 . The flow through the outer channel 15 * can from the second entry 22 to the second exit 24th or vice versa. Depending on the orientation of the flow in the inner tubes 16 and in the inner channel 15 * then there is a heat exchange in cocurrent or in countercurrent.

In the case of a product-to-product heat exchange, the annular gap is S who is already related to the 2a , 2 B was discussed, cleaning-critical, because the second product P2 , which can penetrate here during the product journey, can only be completely cleaned off by overdosed CIP cleaning or cannot be adequately cleaned even under particularly difficult conditions.

Welded joints

The one in the 2a , 2 B and 3rd disclosed annular gap S is eliminated when the welded joint between the inner tube 16 and the tube support plate 12th , 14 , as in a first welded connection in 4th shown and known per se, is designed. The first welded joint is characterized by the fact that the inner tube 16 with its inner bore 17th in a plane perpendicular to the inner tube longitudinal axis R with a the inner tube 16 facing end of the disc-shaped tube support plate 12th , 14 which has the same internal bore 17th has connected. The inner bore 17th of the inner tube 16 and that of the tube support plate 12th , 14 have the same internal diameters D and are aligned with each other. A circumferential circular weld 36 is related to the pipe support plate 12th , 14 to one upstream axial form fit distance B2 a first form fit F1 from the pipe support plate 12th , 14 positioned away with the pipe support plate 12th , 14 in this area except for a tube wall thickness d endured.

The inner tube is in an unwelded starting position 16 and the pipe support plate 12th , 14 through the first form fit F1 , which is effective radially and axially and directed against each other, fixed to each other. For this purpose, the tubular necking of the tube support plate 12th , 14 one to the inner tube longitudinal axis R coaxially oriented plate-side internal recess 26 on, which has an axial form-fitting depth in the axial direction B1 and has a tube-side external recess 32 that has the same form fit depth B1 owns, encompasses outside and coaxially.

A welding tool 40 is in the direction of the inner tube longitudinal axis R into the inner bore 17th introduced and leads with a perpendicular to the inner bore 17th oriented welding electrode 42 the all-round circular weld 36 with an orbital movement U , single-layer and consistent from the inside to the outside. This creates a weld seam width b the circumferential circular weld 36 set up so that it has at least the axial positive locking depth B1 the first form closure F1 detected.

In the course of the individual weld and over the entire welding sequence of all welds for a set of inner tubes 16 that with the associated pipe support plate 12th , 14 the inner tubes are to be welded 16 and the pipe support plate 12th , 14 with a contact pressure PR pressed against each other.

With the inner tube used 16 with the inside diameter D , the pipe wall thickness d and an inner tube length L is a slim, thin-walled inner tube 16 that with the massive tube support plate 12th , 14 which is a panel wall thickness B has to be welded. The specific quantitative respective dimensions depend on the size of the tube bundle 10th and depending on its heat transfer capacity and can therefore only be given in a general view by the following proportions of dimensions: $$\text{D}/\text{d}>\mathrm{10th};\text{L}/\text{D}>100\text{and B}/\text{d}>\mathrm{10th}$$

4a shows a second welded connection between the inner tube 16 with the inner bore 17th and the tube support plate 12th , 14 with the same diameter inner bore 17th . The inner tube is in an unwelded starting position 16 with the tube wall thickness d and the pipe support plate 12th , 14 through the first form fit F1 , which is effective radially and axially and directed against each other, fixed to each other. For this purpose, the tubular necking of the tube support plate 12th , 14 with their upstream axial form-fit distance B2 one to the inner tube longitudinal axis R coaxially oriented plate-side external recess 28 with a recess wall thickness a on, the axial form-fitting depth in the axial direction B1 and that in a tube-side internal recess 30th that has the same form fit depth B1 owns, intervenes inside and coaxially.

A third weld connection between the inner tube 16 with the inner bore 17th and the tube support plate 12th , 14 with the same diameter inner bore 17th is in 4b shown. This is where the first form fit is realized F1 only in the neck of the tube support plate 12th , 14 the plate-side internal recess 26 which is the full pipe wall thickness d with the axial form-fit depth B1 encompasses coaxially on the outside, the radial dimension of the wall thickness of the neck, which extends over the upstream axial interlocking distance B2 extends the pipe wall thickness d around the recess wall thickness a exceeds.

In a fourth welded joint ( 5 ) and in a fifth welded joint ( 6 ) uses the first form closure F1 the inner tube 16 that in its inner bore 17th the same inside diameter D like the inner hole 17th in the tube support plate 12th , 14 has, with the full pipe wall thickness d and with the axial form-fit depth B1 directly into the end face of the tube support plate 12th , 14 a. When executed according to 5 is the axial form-fit depth B1 of the internal recess on the plate side 26 dimensioned so that the necessary weld width b the circumferential circular weld 36 only partially within the tube support plate 12th , 14 is located and the other part of a section of the outside free inner tube 16 detected. When executed according to 6 is the axial form-fit depth B1 of the internal recess on the plate side 26 maximum, and dimensioned such that the necessary weld width b the axial form-fit depth B1 completely captured and thus completely in the tube support plate 12th , 13 , from the side of the inner tube 16 seen from intervenes.

In order to avoid a discontinuous, in the present case an abruptly changing cross-sectional profile of the wall thicknesses to be welded, the fourth weld connection is in accordance with 5 thereby compared to the fifth welded joint 6 modified that the tube support plate 12th , 14 radially outside of the circumferential circular weld 36 a circumferential, axially extending, annular gap-shaped plate-side recess 34 having. With regard to its radial position and width, this is designed in such a way that that with the circumferential circular weld seam 36 Wall thickness of the pipe support plate to be welded 12th , 14 assumes a value between the simple to the double pipe wall thickness d lies (see also 7a , 7b) .

The in the 4th , 4a , 4b , 5 and 6 Welded connections described are task with an innovative device according to the invention 50 ( 8th , 9 and 10th ) realized. That with the auxiliary device 50 feasible process assumes that the pipe support plate 12th , 14 by specifying more than one inner hole 17th a pipe layout pattern M specifies ( 7 ) for the arrangement of assigned inner tubes arranged parallel to each other 16 . The plate rotation axis A the tube support plate 12th , 14 does not necessarily have to have an inner tube 16 be occupied. The limiting limit for a number n Inner tubes 16 is given if there is only one possible partial circle T ( 10th ; a multiple pitch circle arrangement is with the proposed auxiliary device 50 not realizable) the inner tubes to be arranged on this 16 under the given heat transfer conditions (necessary distances of the inner pipes 16 from each other) can no longer record.

The auxiliary device 50 sets the necessary number n Inner tubes 16 in accordance with the pipe layout pattern M to each other and in the respective first positive connection F1 with the pipe support plate 12th , 14 by means of a second positive connection F2 immovably firm ( 9 , 10th ). Over the duration of the welds for all inner tubes 16 becomes the pipe support plate 12th , 14 in the direction of the inner tube longitudinal axes R to the inner tubes 16 with a contact pressure PR pressed on ( 9 ; Pipe support plate 12th , 14 is not shown) and there are the inner tubes 16 one after the other with the pipe support plate 12th , 14 welded.

In this regard, a welding sequence provides that, if present, first the central inner tube 16 and then the one on the pitch circle T around the central inner tube 16 external inner tubes arranged around 16 , each in the opposite sequence, with the tube support plate 12th , 14 be welded.

• • Das Innenrohr 16 mit seiner Innenbohrung 17 ist in einer Ebene senkrecht zu der Innenrohrlängsachse R mit einer Stirnseite der scheibenförmigen Rohrträgerplatte 12, 14 , die eine ebensolche Innenbohrung 17 aufweist, verbunden.
• • Die Innenbohrung 17 des Innenrohres 16 und jene der Rohrträgerplatte 12, 14 weisen gleichgroße Innendurchmesser D auf und sind miteinander fluchtend ausgerichtet.
• • In einer unverschweißten Ausgangslage sind das Innenrohr 16 und die Rohrträgerplatte 12, 14 mit dem ersten Formschluss F1, der radial sowie axial und gegeneinander gerichtet wirksam ist, zueinander festgelegt.
• • Die umlaufende Rundschweißnaht 36 ist orbital, von der Innenbohrung 17 ausgehend, einlagig und durchgängig von innen bis außen ausgeführt.
• • Die Schweißnahtbreite b der umlaufenden Rundschweißnaht 36 erfasst mindestens die axiale Formschlusstiefe B1 des ersten Formschlusse F1.

The auxiliary device according to the innovation 50 ( 8th , 9 , 10th ) enables a welded connection that is designed as follows:

• • The inner tube 16 with its inner bore 17th is in a plane perpendicular to the inner tube longitudinal axis R with an end face of the disc-shaped tube support plate 12th , 14 which has the same internal bore 17th has connected.
• • The inner bore 17th of the inner tube 16 and that of the tube support plate 12th , 14 have the same internal diameters D and are aligned with each other.
• • The inner tube is in an unwelded starting position 16 and the pipe support plate 12th , 14 with the first positive locking F1 , which is effective radially and axially and directed against each other, fixed to each other.
• • The all-round circular weld 36 is orbital, from the inner bore 17th outgoing, single-layer and continuous from the inside to the outside.
• • The weld width b the circumferential circular weld 36 records at least the axial form-fit depth B1 of the first form closure F1 .

The auxiliary device 50 consists of a first and a second retaining ring half 50.1 , 50.2 which form a closed ring together after joining. The retaining ring halves 50.1 , 50.2 touch in a dividing plane E going through a center Z the auxiliary device 50 runs, and in this parting plane E form the retaining ring halves 50.1 , 50.2 over a parting line contour 50.1a and a parting line opposite contour 50.2a ( 8th , 10th ) the immovable second form fit F2 together.

Preferably, the second form fit F2 the first and second half-ring halves 50.1 , 50.2 fixed in the radial direction to each other. The first and second half-ring halves 50.1 , 50.2 are also advantageous due to the circumference of the first and second half-ring halves 50.1 , 50.2 arranged connecting screw 56 , which are arranged diametrically to each other, releasably connected together. As a result, the radially oriented second form fit F2 additionally fixed and an axial displacement of the retaining ring halves 50.1 , 50.2 against each other prevented.

The pipe support plate 12th , 14 sets by specifying more than one internal bore provided in it 17th the pipe layout pattern M fixed for the arrangement of inner tubes arranged parallel to each other 16 ( 7 , 7a , 7b) . The pipe layout pattern M is in the retaining ring halves 50.1 , 50.2 mapped so that on the single pitch circle T evenly distributed inner tubes 16 each half of the retaining ring halves at most 50.1 , 50.2 are enclosed ( 10th ), the opening of the respective surrounding contour the center Z the auxiliary device 50 is facing. The parting line E additionally runs through at least one on the pitch circle T horizontal inner tube longitudinal axis R an inner tube 16 . They are holding bolts 52 provided, each on the circumference of the retaining ring halves 50.1 , 50.2 and with a retaining pin longitudinal axis r star-shaped towards the center Z oriented towards the halves of the retaining ring 50.1 , 50.2 slidable in the direction of the longitudinal axis of the retaining ring r intervention. The retaining bolts 52 touch with their lateral surface on the pitch circle T arranged, adjacent inner tubes 16 . The retaining bolts 52 put with their respective the center Z facing end face if necessary in the center Z arranged inner tube 16 and are releasably set in this position ( 10th ). The retaining bolts 52 are preferably each by a locking screw 54 in the assigned retaining ring half 50.1 , 50.2 fixed immovably.

In the embodiment of a particularly advantageous pipe assignment according to the 7 , 7a , 7b are seven inner holes 17th provided, with an inner bore 17th coaxial to the plate rotation axis A the tube support plate 12th , 14 and six inner holes 17th evenly distributed on the pitch circle T ( 8th , 9 , 10th ) are arranged. In this case the parting line runs E additionally through two diametrically arranged inner tubes 16 ( 10th ).

The definition of the inner tubes 16 in the auxiliary device 50 through retaining bolts 52 can also be carried out in a manner other than that described above, for example by means of displaceable and fixable shaped pieces which extend in the axial direction from that of the tube support plate 12th , 14 opposite side in an annular, detachably divisible auxiliary device 50 between the inner tubes 16 be inserted and fix the inner tubes immovably. Any configuration of the auxiliary device 50 that have the set of inner tubes 16 during the welding sequence immovably and the inner tubes 16 entirely in the first form fit F1 opposite the pipe support plate 12th , 14 adjusted and against the latter with the contact pressure PR pressed, enables the procedure for welded connections between inner tubes to be carried out 16 and tube support plates 12th , 14 of a tube bundle 10th for a product-to-product tube bundle heat exchanger.

The present innovation further claims a tube bundle 10th for a product-to-product tube bundle heat exchanger 100 , as it is known in its basic structure in the prior art and in the 3rd in connection with the 2a , 2 B is shown. In contrast to this known version, the critical annular gap S thereby avoiding the tube bundle 10th in this area with an auxiliary device 50 for a process for welded connections between inner tubes 16 and tube support plates 12th , 14 is welded according to one of claims 1 to 8.

The present innovation further claims a product-to-product tube bundle heat exchanger with at least one tube bundle 10th , as it is known in its basic structure in the prior art and in the 3rd in connection with the 2a , 2 B is shown. In contrast to this known version, the critical annular gap S thereby avoiding the tube bundle 10th is welded in this area according to claim 9.

Reference symbol list

100

Tube bundle heat exchanger

5

Connecting elbow

10th

Tube bundle

12

first tube support plate

14

second tube support plate

15

Outer tube

15 *

Outer channel

16

Inner tube

16 *

Inner channel

17th

Inner bore

18th

first entry

20th

first exit

22

second entry

24th

second exit

26

Internal recess on the plate side

28

External recess on the plate side

30th

tube-side internal recess

32

tube-side external recess

34

plate-side recess

36

all-round circular weld

40

Welding tool

42

Welding electrode

50

Auxiliary device

50.1

first retaining ring half

50.1a

Parting line contour

50.2

second retaining ring half

50.2a

Separating plane counter contour

52

Retaining bolt

54

Locking screw

56

Connecting screw

A

Plate rotation axis

B

Panel wall thickness

B1

axial form fit depth

B2

upstream axial form fit distance

D

Inside diameter

E

Dividing plane

F1

first positive locking

F2

second form fit

L

Inner tube length

M

Pipe assignment pattern

P1

first product

P2

second product

PR

Contact pressure

R

Inner tube longitudinal axis

S

Annular gap

SN

Weld

T

Pitch circle

U

orbital movement

Z

center

a

Recess wall thickness

b

Weld width

d

Pipe wall thickness

n

Number (inner tubes; inner bores)

r

Retaining pin longitudinal axis

D / d> 10

Ratio of the inner diameter of the inner tube to the tube wall thickness

L / D> 100

Ratio of the inner tube length to the inner diameter of the inner tube

B / d> 10

Ratio of plate wall thickness to pipe wall thickness

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• JP 2020117121 [0007]
• US 2996600 A [0008]
• WO 2014060425 A1 [0009]
• DE 9403913 U1 [0025]

Claims (10)

Auxiliary device (50) for a method for welded connections between inner tubes (16) and tube support plates (12, 14) of a tube bundle (10) for a product-to-product tube bundle heat exchanger (100), the welded connection being in a manner known per se the inner tube (16) is connected with its inner bore (17) in a plane perpendicular to an inner tube longitudinal axis (R) to an end face of the disk-shaped tube support plate (12, 14), which has the same inner bore (17), • that the inner bore (17) of the inner tube (16) and that of the tube support plate (12, 14) have equal inner diameters (D) and are aligned with each other, • that in an unwelded starting position the inner tube (16) and the tube support plate (12, 14) are fixed to one another with a first positive connection (F1), which is effective radially, axially and in a mutually directed manner, • that a circumferential circular weld seam ( 36) orbital, from the inner bore (17), is single-layer and continuous from the inside to the outside and • that a weld seam width (b) of the circumferential circular weld seam (36) detects at least one axial form-fit depth (B1) of the first form-fit (F1), characterized in that • that a first and a second retaining ring half (50.1, 50.2) are provided, which form a closed ring, • that the retaining ring halves (50.1, 50.2) are in a parting plane (E) through a center (Z) of the Auxiliary device (50) runs, touch and that in the parting plane (E) the retaining ring halves (50.1, 50.2) form an immovable second positive connection (F2) with each other, • that the tube support plate (12, 14) by specifying more than one in it provided inner bore (17) defines a tube occupancy pattern (M) for the arrangement of inner tubes (16) arranged parallel to one another, • that the tube occupancy pattern (M) in the retaining ring halves (50.1, 50.2) such It is shown that the inner tubes (16), which are arranged in a uniformly distributed manner on a single pitch circle (T), are each surrounded on a maximum half side by the retaining ring halves (50.1, 50.2), the opening of the respective surrounding contour being at the center (Z) of the retaining ring halves (50.1, 50.2) facing, • that the parting plane (E) additionally runs through at least one inner tube longitudinal axis (R) lying on the pitch circle (T), • that retaining bolts (52) are provided, each on the circumference of the retaining ring halves (50.1, 50.2) and in a star shape Center (Z) oriented to engage in the retaining ring halves (50.1, 50.2) so that • the retaining bolts (52) on the pitch circle (T) arranged adjacent inner tubes (16) each tangent and • that the retaining bolts (52) with their respective If necessary, fix an inner tube (16) arranged in the center (Z) to the end face facing the center (Z) and are detachably fixed themselves in this position. Auxiliary device (50) after Claim 1 , characterized in that the second positive connection (F2) fixes the first and the second half-ring halves (50.1, 50.2) in the radial direction to one another. Auxiliary device (50) after Claim 1 or 2nd , characterized in that the retaining bolts (52) are immovably fixed in each case by a locking screw (54) in the associated retaining ring half (50.1, 50.2). Auxiliary device (50) according to one of the preceding claims, characterized in that the first and second half-ring halves (50.1, 50.2) are arranged diametrically to one another by a connecting screw (56) arranged on the circumference of the first and second half-ring halves (50.1, 50.2) are releasably connected. Auxiliary device (50) according to one of the preceding claims, characterized in that • seven inner tubes (16) are provided, one inner tube (16) being located coaxially in the center (Z) and six inner tubes (16) evenly distributed on the pitch circle (T) are arranged and • that the parting plane (E) additionally runs through two diametrically arranged inner tubes (16). Auxiliary device according to one of the preceding claims, characterized in that the circumferential circular weld seam (36) is positioned in such a way that the weld seam width (b) does not exceed the form-fit depth (B1) in the tube support plate (12, 14) from the side of the inner tube (16 ) seen, intervenes. Auxiliary device according to one of the Claims 1 to 5 , characterized in that the circumferential circular weld seam (36), with respect to the tube support plate (12, 14), is positioned away from the tube support plate (12, 14) by an upstream axial form fit distance (B2) of the first form fit (F1), the Pipe support plate (12, 14) in this area to a wall thickness between the single to double the tube wall thickness (d) is necked. Auxiliary device according to one of the preceding claims, characterized in that the tube support plate (12, 14) radially outside of the Circumferential circular weld seam (36) has a circumferential, axially extending, annular-gap-shaped plate-side recess (34) which is designed such that the wall thickness of the tube support plate (12, 14) to be welded to the circumferential circular weld seam (36) assumes a value between the simple to twice the tube wall thickness (d). Tube bundle (10) for a product-to-product tube bundle heat exchanger (100), welded with an auxiliary device (50) for a method for welded connections between inner tubes (16) and tube support plates (12, 14) according to one of the Claims 1 to 8th . Product-to-product tube bundle heat exchanger (100) with at least one tube bundle (10) which according to Claim 9 is welded.

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